Quantum3D cards were not generic constructions (mostly) which outperformed reference cards.
With theirs unique design they are pearls in each 3dfx collection.
Obsidian2 cards have DB-26HD connector (excl. TV-Out) instead common VGA socket. To expose 3D output either pair with 2D card, special cable so called Medusa was required.
Reproduction of Medusa cable
Genuine Medusa cable